Sci Foo: Rewriting gravity over a tuna roll

It's Sunday evening in Mountain View, California. Theoretical physicist Erik Verlinde, from the University of Amsterdam, is munching sushi and telling me about a holiday he took in France last year. The day before he was due to return home, the house where he was staying was burgled. Stuck for several days without money or passport, Verlinde decided to relieve the stress by working, and came up with an idea about the nature of gravity that he believes could revolutionise physics.

Earlier in the day, we had attended the closing session of Science Foo camp, an "unconference" being held at Google headquarters, at which more than three hundred people from all fields of science were thrown together and asked to talk to people we didn't know, and attend sessions we knew nothing about.

Brightly-coloured chairs that had started off in neat rows were now scattered, and a small tent with several low camping seats was sitting incongruously in the middle of the floor. As we milled around, conference organiser Tim O'Reilly called a selection of people to give 45-second summaries of their time at SciFoo.

Among those to take the stage were Yves Rossi ("Jetman"), who by strapping a 2.5-metre carbon
wing and 4 jet engines to his back, has been able to turn himself into
a human jet plane. He steers in the air using tiny movements of his
head, shoulders and arms, and in September 2008, he flew across the
English channel.

Also to step up is Harry Kloor, who among many other things is chief
scientific advisor to the X Prize Foundation
and has written for Star Trek: Voyager. He told us about his new film
Quantum Quest, a 3D science fantasy
animation based on the Cassini-Huygens
mission to Saturn, in which Hollywood
stars from Samuel L. Jackson to Chris Pine and William Shatner voice
characters such as a photon, a neutrino and the void before the Big
Bang.

And neuroscientist David Eagleman (and author of
the brilliant Sum: Forty tales from the Afterlives) told us that our
perception of time is inextricably bound up with memory, so the more
memories we lay down during a particular period of time, the longer it will seem to have lasted - which explains why for most of us, this
weekend feels as if it has lasted a week.

Then it was time for applause and the conference was over. But one of
the best things about SciFoo has been the ease of chatting with
unexpected people - in the dinner queue, on the bus - even with those
big names who might usually be daunting to approach. The mix of
disciplines has created the sense of a level playing field, in which we are united by curiosity and an enthusiasm for new ideas. Hopefully that's
something we'll all be able to take home with us (in addition to our
other SciFoo gifts: a Google-logo notebook, a surprisingly cool
t-shirt, and a very heavy engraved plastic cube).

And so at dinner, at a not-half-bad sushi restaurant, Verlinde patiently attempts to summarise his ideas about
gravity in a way that I can understand. There are generally thought to
be four fundamental forces in the universe that govern how particles
interact - gravity, electromagnetism, the weak nuclear force and the
strong nuclear force. You can't derive these from equations or explain
them, they're just a fundamental part of how our universe is.

Verlinde's big idea is that gravity is not fundamental at all. It's
just an emergent property, or side effect, of something else that's
happening. Just as an elastic band will contract if it is stretched
from its normal length, Verlinde reckons the universe has been pushed
out of equilibrium, and that gravity is the result of it shifting back
to a stable state. He published his ideas in a
preprint in January (covered by New
Scientist at the
time), but an article on his work recently published in the New York
Times has
now turned Verlinde into something of a science celebrity.

What pushed the universe out of equilibrium? Well, Verlinde believes that the big bang is an illusion too, and that (if I have understood correctly) the universe's expansion is
just another sign of space-time returning to its stable state. And in a
steady-state universe that lasts forever, such spontaneous jumps away
from equilibrium are bound to occur eventually (this is a bit like the
argument that says that if a table were to exist for an infinite amount of
time, eventually there is bound to occur a chance event in which all of
its atoms jump into the air at once).

So far all this is just an "intuition", Verlinde says. Now he needs to find
the mathematics to prove it. Then he shrugs and says perfectly
matter-of-factly that this was how Einstein started out too.

Einstein, of course, revolutionised our understanding of the universe.
I might have raised an eyebrow at this point, but after a
mind-expanding weekend at SciFoo, it doesn't seem so far-fetched that
just maybe, Verlinde can too.

6 Comments

Yes' and space is simply the result of burning a pink marshmallow! I agree Gravity is emergent like temperature is emergent from electron flow, but something must still flow, in the case of gravity I believe it's mass-quark interaction (or exchange of forces such as a graviton?) in the neutron.

By Hollowbean
on August 3, 2010 7:00 PM

Not to say that this isn't inspiring to hear people asking these questions, especially about the 4 fundamental forces we assume today, but isn't this gravity questioned already proposed in the work that Hawkings and Bekenstein did? There is a nice section in Green's "The Fabric of the Cosmos" page 426-7 outlining it.

I just recalled reading the section and thought I'd post it here to anyone interested. It involves the black holes, entropy, and some of the cooler concepts in physics.

malcoda
on August 4, 2010 1:21 AM

yes...and this is how Freidrick Vanderhoser started out too. Oh...you don't know that name?...neither does anyone else either!

KrisMerrells
on August 4, 2010 1:37 AM

Well, given how gravity is treated in relativity, it kinda makes sense that it's not really a force unto itself. When a roller coaster car curves to the right along a track, there's no special force on the right of the track pulling the car, the car is simply following the most direct path along the track. When a comets flies by a planet, it doesn't get pulled by the planet, it simply follows the most direct path along spacetime. That's how I understand it, anyway.

Art
on August 4, 2010 8:40 AM

So gravity is still a fundamental force. Just the parts of it may slightly be more well understood. Interesting thinking. Keep learning i'm sure you will find out more.